1. Field
The present disclosure relates generally to the field of humidity control.
2. Description of Related Art
Humidity control products in general are well known. A humectant is a hygroscopic substance which is used to maintain moisture in an environment. Humectants that form the prior art often use saturated salt solutions to control humidity. However, the saturated salt solutions may emit an odor (e.g., an unpleasant odor) and often have a short life span (e.g., between about 30 to 45 days).
Oxygen control of various products, including food and pharmaceuticals, for example, is also desirable, because oxygen can be detrimental to food and pharmaceuticals and can advance spoilage of these products. Typical oxygen absorbers (or oxygen scavengers) use oxidation of iron or a similar metal to reduce oxygen in an environment, and require water to activate.
Often times, it is desirable to control both humidity and oxygen in the same environment. However, because oxygen absorbers often require water to activate, the oxygen absorber and humectant (or desiccant) must be separately packaged in order to maintain desired performance of both the oxygen absorber and the humectant/desiccant. As such, the humidity and oxygen controlling components may take up significant space in an enclosed environment (such as a pill bottle), thus reducing the amount of product that can be placed in the pill bottle or requiring the use of a relatively large pill bottle.
Humidity indicator cards (or HIC or humidity indicating cards) are designed to change color when the humidity level of an environment around the HIC exceeds or drops below a predetermined level. The HIC typically includes a visible indicator that indicates to a user when the humidity level of an environment exceeds or drops below a predetermined level. For example, the HIC may include a color-indicator that changes color when the HIC is exposed to a level of humidity that is greater than the predetermined level.
Humidity indicator cards are often used in contained environments. For example, an HIC is often placed in sealed packaging to provide a user means for determining and monitoring the humidity level inside of the packaging. Humidity indicator cards may be used in a wide variety of industries. For example, humidity indicator cards may be used in packaging for food, drugs, medical devices, and/or sensitive electronics. In some applications, for example when monitoring the humidity of tobacco and/or other drugs, it may be desirable for a user to monitor humidity of the product and its environment throughout the life of the product. In other applications, for example, produce shipments, the humidity indicator cards may be used when shipping to a wholesaler or retailer, but may be discarded prior to reaching the final intended user or consumer.
In some environments, surveillance and/or tracking of a product in addition to monitoring of humidity levels of the product may be desired. Various methods for surveillance, inventory tracking, traceability, security, and inventory management are known, including radio frequency identification (RFID) tags, ultrahigh frequency (UHF) sensors, electronic article surveillance (EAS) tags, electronic humidity recording tags and inlays (e.g., a SMARTRAC® DogBone RFID inlay), etc.
As an example, EAS tags, sometimes called source tags, are often used on high-value products. The EAS tags are normally deactivated (typically magnetically) at a checkout counter, but if not deactivated, a shoplifted product is detected at a store's exit to alert security personnel. Typically, EAS tags are placed on the product or on the inside or outside of a product carton (or on the outside of a product container such as a pharmaceutical bottle) where it may be detected and surreptitiously removed by an experienced shoplifter. However, placement of an exposed tag directly within certain types of products, such as foods or drugs, is unacceptable in view of FDA and other regulations which sharply limit the materials permitted to contact such products. Further, because the EAS tags often use one of acoustic-magnetic, radio frequency, microwave, and electromagnetic technology, it is generally undesirable to place the EAS tags in an environment having any moisture. Similar issues arise with the use of RFID, UHF, electronic humidity indicating inlays, and other similar tags or sensors.